Process for drawing sheet glass



July 2s, 1931. J BRAKE 1,816,179

PROCESS FOR D'RAWING SHEET GLASS Filed Aug. 2, 192s 4e-2M v 5- v nvenlo'b c/o/m L Dra/fe alto: nu,

Patented July v"1931 cooled.

so vide Eni' lwith the roll will become t AUNITED STATES PATENT OFFICE JOHN L. BRAKE, OF TOLEDO, OHIO, ASSIGNOB TO LIIBBEY-OWENS-FOBD GLASS CO1-,v

P ANY; OF TOLEDO, OHIO, .A CORPORATION 0F OHIO PROCES FOB DRAWING SHEET GLASS Application led August 2, 1926. Serial No. 126,608.

This invention relatesto new and useful improvements in the art of drawing sheet lass, and more particularly to novel means or treating the sheet adjacentthe sheet source.

In certain systems for continuously drawing sheet glass from a pool of molten glass, such as for example that4 set forth in the atent to Colburn, ecember 4, 1917, the sheet is drawn upwardly and subsequently horizontally over al bending roll which is cooled in any desired manner. However,

one 'of these bending rolls in provided consequently as the sheet is deflected thereover, that side of the sheet contacting more uickly the opposite side t ereof.

initially cooled than will Thus, with such an arrangement both sides of the sheet are not uniformly and evenly Also, in such systems as referred to hereinabove, thebending roll is positioned above and somewhat distant from the sheet source so that the sheet drawn therefrom has a tendency to` narrow, and unless means is provided for overcoming this tendency the sheet will soon pull to a string or thread. Con uently, various means have been prodmior treating the edges of the sheet in order to maintain the desired width thereof throughout its entire length.

portant object of the present invention is to provide sheetY forming means which will have an equalized cooling effect on opposite sides of the sheet being drawn.

Another object of the invention is tov accomplish this equalized cooling of the sheet by passing a mass of molten glass between rotatable members, so arranged that opposite surfaces of the -sheetl contact ual amounts with the surfaces of the. rotable members. l Another important object ofthe present invention is the provision of sheet forming members constructed and arranged relative to one another immediately adjacent' the sheet source so that they will also serve to maintain the proper width of the sheet throughout its entire length, ,and thus elim- No. 1,248,809, granted l deflected inate the necessity of employing extraneous edge treating means.

The present invention also embodies other objects and advantages which will become more readily apparent during the course of the following description when taken in connection withthe accompanying drawings.

In the drawings forming the part of this application Fig. 1 is a transverse vertical sectional view through portions of the sheet drawingl apparatus embodying the present invention and showing one form of the improved sheet forming means,

Fig. 2 is a transverse sectional View through the draw pot showing the improved sheet forming members in elevation,

Fig. 3 lis a transverse vertical sectional view showing a somewhat modified form of the present invention, and

Figs. 4.-, 5 and 6 are views similar to Fig. 3, showing further modified forms of the invention.

Referring now more in detail to the accompanying drawings, and especially to Figs. 1 and 2, the numeral 5 generally designatesthe usual draw, pot of conventional construction, mounted upon stools 6, arranged in the heating chamber 7, and containing the molten glass 8 from which the sheet is to be drawn.

In practicing the method embodying the present invention, the glass in desired quantity is drawnupwardly and from the glass 8 in the draw-pot 5 initially by means of a bait, and while the glass is still in its mass formation as at' 9, it is deflected horizontally over a lower bending roll 10, and is passed betweenl this roll and the upper roll 11, which is positioned directly above the lower roll 10. As the glass passes --between these rolls 10 and 11, it is ironed and reduced to sheet form as will be .apparent from the drawings. After being deflected over the" lower roll 10, the path of travel of the glass is reversed and it is deflected in the opposite direction over the upper roll 11. Thus, the sheet is first deflected in a clockwise direction about the lower roll l0, and subsequently in a counter-clockwise direction over the upper roll 11. The drawn sheet, designated at, 12, is preferably supported intermediate the bending and drawing means by a plurality of spaced idler rollers 13 which prevent sagging of the soft or plastic portions of the sheet. The drawing means has not been disclosed in the drawings.

rlhe rolls 10 and 11 may be formed of suitable non-corrosive material such as nichrome, Monel metal, or the like, and are essentially hollow so that a suitable cooling agent such as water or air may be forced therethrough. These rolls therefore not only act as sheet forming members, but alsov serve to cool the glass as it passes over them. Consequently, the rolls 10 and 11 serve the double function of bending rolls and cooling rolls. It will be evident that, as the glass passes over the lower roll 10, the side of the glass contacting with said roll will be somewhat cooled thereby, and that when the path of travel of the sheet is reversed and the sheet passes over the upper roll 11, the side contacting therewith will be cooled an equal amount. Thus, one side of `the glass is cooled as it passes over the lowerrpll 10, and the opposite side thereof is cooled as it passes over the upper roll 11. Inasmuch as o posite surfaces of the sheet contact equa amounts with the surfaces of the rolls 10 and 11, the said rolls therefore serve to effect an equal cooling of the opposite sides of the sheet which will result in the production of a higher grade of glass.

The opposite ends of the rolls 1.0 and 11 may be journaled in suitable bearings 14, and the upper roll 11 is preferably mounted therein for vertical movement so that the space between the rolls can be increased or decreased according to the thickness of glass desired. The vertical adjustment of the upper roll 11 may be readily accomplished by suitable adjusting means such as screws 15 carried by thel bearings 14.

A pair of internally cooled shields 16 and 17 are positioned substantiall parallel to the lower roll 10 and closely adjacent thereto and to the surface of the molten glass 8. These shields serve to protect the sheet land sheet sourcev from the hot gases passingl out from the furnace beneath the lip tiles 18 and 19 and from the radiated heat from the molten glass, and also absorbheat from the molten glass as it is being drawn into the sheet, thus lowering its temperature and increas/ing its .tenacity so that a more.rapid drawing rate is made possible'.

In Fig. 3, wherein has been shown a somewhat modified form of the present invention, there is, associated with the rolls 10 and 11,

a pressing or ironing roll 2Q positioned at one side of and' immediately adjacent the drawn from rst over the upper roll 11. The glass bein the draw pot 5 is deflected lower roll 10, and passes between the same and the upper roll 11, after which it is deflected in the opposite direction over the upper roll 11, and passes between the same and the pressing or ironing roll 20. In Fig. 4, there is also provided a pressing yor ironing roll 21, but in this form of the invention the ironing roll is positioned immediately above the upper roll v11 instead of at one side thereof.

In Fig. 5, there is provided a tank 22 for containing the mass of molten glass 23 which flows therefrom between the refractory lips 24 in the form of a sheet 25. Positioned adjacent the lips 24 are the vertically alined upper and lower rolls 26 and 27. The sheet 25 is deflected initially about the upper roll 26, and is then passed between this roll and the lower roll 27. The sheet can then be drawn vertically downward if desired, or it can be deflected horizontally about the lower roll 27 and passed onto a plurality of horizontally alined supporting rolls 28.

In the form of the invention shown in Fig. 6, the mass of molten glass 29, contained in the tank 30, is adapted to flow vertically downward therefrom between the refractory lips 31 and 32. Positioned immediately adjacent and beneath the lips 31' and 32 are the vertically alined rolls 33 and 34. The mass of glass owing from .the

tank 30 contacts lfirst with the upper roll 33, and is defiected about the said roll in a counter-clockwise direction. As the glass passes between the upper roll and the lip 32, it is reduced to sheet form as indicated at 35. The sheet is then passed between the upper and lower rolls 33 and 34, and subsequently deflected about the lower roll 34 in a clockwise direction. The sheet then passes onto a plurality ofhorizontally alined supporting rolls 36. Of course, if desired, the sheet 35 can be trained first about the upper roll 33 in a clockwise direction, and subsequently about the'lower roll 34 in a counter-clockwise direction.

From the foregoing, it is believed that the construction and application of, together with the advantages to be derived from the present invention will be readily` appreciated, and `it will of course be understood that that any changes or modifications as fall within the scope of the subjoined claims may be made without departing from or sacrificing the spirit of the invention.

Claims:

1. The method of forming sheet glass, consisting in drawing a sheet of glass from a mass of molten glass, deflecting the sheet in one direction and reducing it to a substantially predetermined thickness and then subsequently deflecting the said sheet in the opposite direction.

2. The method of forming sheet glass, consisting in drawing a sheet of glass from a mass of molten glass, deecting the sheet in one direction and passing it between moving surfaces to reduce it to a substantially predetermined thickness, and then deiiecting the sheet in the opposite direction about one of said moving surfaces.

3. The method of forming sheet glass, consisting in drawing a massof glass from a molten source, passing the mass laterally between a pair of members and extending it lengthwise to form a sheet, andv subsequently deiecting the sheet in the opposite direction.

4. The method of forming sheet glass, consisting in drawing a'mass ofglass from a molten source, passing the mass over a sheet forming member and extending it lengthwise to form a sheet, and subsequently deflecting the sheet in the oppgsite direction over a second sheet formingmember.

5. The method of forming sheet glass, consisting in drawing a mass of' glass from a molten source, passing the mass laterally over a member to cool one side of said glass and extending it lengthwise to form a sheet, and subsequently deieoting the sheet in the opposite direction, and passing the same over a second member to cool the opposite side of said sheet.

6. The method of forming sheet glass, consisting yin drawing a mass of glass from a molten source, passing the mass laterally over a member to cool one side of said glass and extending it lengthwise to form a sheet, and subsequently deiecting the sheet in the opposite direction, and passing the same over a second member to cool the opposite side of said sheet, the opposite sides of the glass engaging themembers at opposite sides of the vertical axes thereof.

7 The method of forming sheet glass, consisting in drawing a mass of glass from a -molten source, passing the mass laterally 'over amember and extending it lengthwise to form a sheet, and subsequently deflecting the sheet in the opposite direction and passing the same over a second member whose axis is arranged in the same vertical plane with the axis of the first named member.

Signed at Toledo, in the county of Lucas and State of Ohio, this 30th day of July,

JOHN L. DRAKE. 

